الفهرس 
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Abstract
Acne vulgaris is one of the most common skin conditions that is encountered by the dermatologist and other specialties on a daily basis. It causes much distress to the patients. Clinically, it has long been observed that many acne patients improve upon exposure to sunlight. It was assumed that ultraviolet light was responsible, which led to an expanded interest in light-based therapies for acne (Bhardwaj et al., 2005).
It is a multifactorial disease involves four main pathways.:1) Excess sebum production. 2) Abnormal keratinization of the follicles leading to plugging and comedone formation.3) Propionibacterium acnes colonization.4) Inflammation of the follicle and surrounding dermis.
There are many therapeutic modalities available for the treatment of acne vulgaris including topical antibiotics, topical retinoids, benzoyl peroxide, oral antibiotics, systemic retinoids and hormonal therapy. All these previous modalities are variably effective, frequently irritant and usually cause problematic side effects. More over these modalities require long duration of treatment.
Although antibiotics are the standard treatment of acne, bacterial resistance to antibiotics is becoming an increasing problem making an alternative option for acne treatment is desirable.
Increasingly over the past decade, lasers and light-based therapies have been introduced as alternative treatements for acne, including intense pulsed light (IPL), pulsed dye lasers (PDL), potassium titanyl phosphate lasers (KTP), infrared diode lasers, broad-spectrum continuous-wave visible light sources (blue light, blue-red light), and photodynamic therapy (PDT) with with photoactivation of aminolevulinic acid (ALA) or methyl-aminolevulinic acid (MAL) by continuous wave light sources, lasers and IPL systems. The supposed mechanisms of action for optical treatments are photothermal heating of sebaceous glands and photochemical inactivation of P.acnes, which produces coproporphyrins and protoporphyrins. Moreover, photo-immunological reactions may possibly contribute to improve acne (Haedersdal et al., 2008).
Propionibacterium acnes is known to produce endogenous porphyrins, the major component of which is thought to be coproporphyrin III and exposure of these compounds to light in the blue region (415 nm) results in photodynamic stimulation of these porphyrins, singlet oxygen production, and bacterial killing .This reaction is confined to the bacteria and, thus, has no direct effect on the surrounding tissue. Heat causes cells to produce heat-shock proteins, which then kill acne bacteria, hastening the healing of an acne lesion.
The present study aimed at determineing the effect of blue light therapy with wave length of( 415 nm )for treatment of inflammatory lesions in patients with acne vulgaris. Twenty patients suffering from acne vulgaris with different severity grades were studied, in addition to twenty healthy subjects without clinical evidence of acne.
In this study each patient was subjected to blue light therapy 415nm wave length and thermal shock 47 ºc (BT) using CleaneTM acne device for two and half minutes for each lesion for two successive days and this was repeated once after one week in 4 patients.
The present study results showed good response to therapy. Clinical improvement was observed in 80% of cases, with marked or near total clinical improvement seen in 15% of patients. Minimal improvement or no clinical change in outcome was observed in 20% of cases.
The study showed a significant reduction in bacterial colonies counts in acne patients. Prior to therapy, significantly higher counts in patients than in controls were observed. However, following therapy, no differences between patients and controls were observed.
The present study showed a significant reduction in porphyrin levels in all grades of acne patients following therapy with blue light and heat
Additionally, negative significant correlation between the clinical response to therapy and bacterial culture colonies count was also observed
In conclusion, acne phototherapy with blue light and thermal shock are promising treatment modalities suited particularly for mild to moderate lesions of acne. It seems to be an attractive, fast, inexpensive, effective, non-invasive and safe alternative or at least an adjunctive modality to current topical and systemic anti-acne therapies.